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How “POP” Works
POP works by transmitting an extremely short
burst, within the allocated band, to identify
speeding vehicles in trac. Once the target is
identied, or “popped,” the gun is then turned to its
normal operating mode to provide a vehicle
tracking history (required by law).
Note: According to radar gun manufacturers,
tickets should not be issued in pop mode.
How Laser (Lidar) Works
Laser speed detection is actually light detection
and ranging (LIDAR). Laser guns project a beam of
invisible infrared light. The signal is a series of very
short infrared light energy pulses that move in a
straight line, reecting o your car and returning to
the gun. Laser uses these light pulses to measure
the distance to a vehicle. Speed is then calculated
by measuring how quickly these pulses are
reected, given the known speed of light.
Laser is a newer technology whose use is not as
widespread as conventional radar; therefore, you
may not encounter it on a daily basis. And unlike
radar detection, laser is not prone to false alarms.
Because laser transmits a much narrower beam
than does radar, it is much more accurate in its
ability to distinguish between targets and is also
more dicult to detect. As a result, even the
briefest laser alert should be taken seriously.
There are limitations to laser, however. Laser is
much more sensitive to weather conditions than
radar, and a laser gun’s range will be decreased by
anything aecting visibility, such as rain, fog or
smoke. A laser gun cannot operate through glass,
and it must be stationary to get an accurate reading.
Because laser must have a clear line of sight and is
subject to cosine error (an inaccuracy that increases
as the angle between the gun and the vehicle
increases), police typically use laser equipment
parallel to the road or from an overpass. Laser can
be used day or night.
Understanding Your Detector
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